The present invention is directed to an electric valve for pipe organs and more specifically to an electric valve having an armature pivoted by means of ball bearings and a valve member secured thereto which is constructed in a manner to facilitate separation of the valve member from the valve seat and to eliminate undesirable bounce effects.
In designing valves for pipe organs the primary objectives are the reduction of noise in the operation of the valve, the elimination of bounce upon closing of the valve and a reduction in the force necessary to open a valve against the air pressure within the chest.
A conventional electric valve for pipe organs is illustrated in FIG. 1 of the present application wherein the top board 1 of a chest is provided with an air passage 30 having an enlarged beveled seat 31 surrounding the upper end thereof for receiving the foot of a pipe 35 The valve assembly 33 is mounted within the interior 3 of the chest which has not been shown in its entirety by means of a bracket 2. The interior 3 of the chest is maintained at a higher pressure than the atmospheric pressure outside of the chest and air is prevented from entering the foot of the pipe 35 by means of a valve member 4 which is secured to an armature 5. The armature 5 is pivotally mounted on the bracket 2 by means of a hinge pin 12. An electric coil 7 having a pole piece is mounted on the bracket 2 adjacent the armature 5 so that upon energization of the coil 7 the armature 5 will be pivoted counterclockwise as viewed in FIG. 1 to move the valve 4 away from the passage 30 to allow air under pressure to enter the pipe 35. A spring 13 is connected to one end of the armature 5 and the bracket 2 for biasing the armature in the clockwise direction to return the valve member into engagement with the valve seat surrounding the air passage 30 in the top board 1 upon deenergization of the coil 7. The valve 4 is comprised of a soft piece of leather cemented to a resilient material such as soft felt 9 which in turn is cemented to a metal disk 10 attached to the armature 5 by means of a rivet 11 or the like.
In the rest state, the pressure in the pipe is at atmospheric pressure in contrast to the positive increase in pressure within the chamber 3. Consequently the valve 4 is held by pressure against the seat to form a seal. To open the valve, a relatively large amount of power is required to break the seal but once the seal is broken the air pressure on both sides of the valve 4 approaches equality and as a result very little additional power is required to open the valve 4 to its maximum position. The pivoting of the armature 5 on the bracket 2 by means of the hinge pin 12 tends to create a considerable amount of noise due to clearances in the pivoting assembly.
The valve construction illustrated in FIG. 1 is also subject to an undesirable feature referred to as "bounce". As pointed out previously the deenergization of the coil 7 will cause the valve member 4 to move into engagement with the valve seat under the force of the spring 13. As the valve 4 closes the air rushing around the perimeter of the valve into the pipe causes an even greater increase in the velocity of the armature 5 moving toward the closed position. Once the valve 4 is closed, the armature 5 continues to travel due to the inertia of the armature and the resiliency of the felt 9. Once the armature 5 has ceased movement, the potential energy stored within the felt 9 is released thereby causing the armature 5 to move in the opposite direction. Once again, within a short time frame, the velocity of the armature 5 increases to a degree where it has gained sufficient inertia to again open the valve 4. This process can be repeated several times, each time with the armature travelling a shorter distance till all movement ceases with the valve 4 in the closed position. This undesirable reopening of the valve due to bounce causes an undesirable speaking of the pipe 35.